7/21/2019 Derm 5

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10 Dermatopathology

Villus

 •  Projection of papillary dermis covered by alayer of epidermal cells into a cavity

Normal skin anatomy

Scalp skinKey features

 • Numerous follicles that extend down into thepanniculus

  •  Associated sebaceous glands, arrector pili muscles

Facial skin

Key features

 • Thin epidermis • Basket-weave stratum corneum • Hair follicles and sebaceous glands numerous in

the dermis • Demodex  mites common • Eyelid and ear skin have many vellus hair follicles •  In the upper dermis of eyelid skin, skeletal

muscle bundles are present  • On the conjunctival surface of the eyelid, stratum

corneum and hair follicles are absent, but gobletcells are present

Skin of the trunk

Key features

 • Very thick dermis, especially in skin from theback

 • Scattered hair follicles and sebaceous glands  • Projections of fat extend upward to envelop

adnexae

Figure 1-37 Normal scalp with follicles rooted in the fat

Figure 1-38 Sun-damaged facial skin   f0390f0390

Figure 1-39 Sun-damaged skin. Solar elastosis spares

papillary dermis

Figure 1-40 Eyelid

Figure 1-36  Villi, warty dyskeratoma